Stringed musical instrument with piezoelectric transducer providing gate control and music signals

ABSTRACT

A method of creating a wide variety of player-initiated musical effects, which comprises employing a piezoelectric transducer in contact with the string of a guitar or similar plucked musical instrument, and thereby deriving from the string a control pulse upon each release of the string by the pick or fingers of the musician. The control pulse is utilized to control various gating and other means to create numerous rhythm, tonal and special effects. The apparatus comprises a string and associated piezoelectric transducer, in combination with an impedance changer for creating a very high output impedance for the transducer. Pulse separator and amplifier means are provided to separate the control pulse from the tone which is generated upon plucking of the string. Various monostable, bistable, shaper and gate means are provided to generate the desired tonal, rhythm and other effects.

United States Patent 72] Inventor Chauncey R. Evans Costa Mesa, Calif.

[21] Appl. No. 16,819

[22] Filed Mar. 5, 1970 [45] Patented Nov. 9, 1971 [73] AssigneeColumbia Broadcasting Systems, Inc.

New York, N.Y.

I54] STRING ED MUSICAL INSTRUMENT WITH PIEZOELECTRIC TRANSDUCERPROVIDING GATE CONTROL AND MUSIC SIGNALS 31 Claims, 5 Drawing Figs.

[52] U.S.Cl 84/1.I6, 84/1.03, 84/l.13, 84/1.24,84/D1G. 11 [51] lnt.ClGl0h3/00, GlOh H02 [50] Field of Search 84/ 1.03, 1.13, 1.16, 1.24,1.25, 1.26, DIG. l1,DlG. 12, D16. 30

[56] References Cited UNITED STATES PATENTS 3,217,079 11/1965 Murrell84/1.16 3,223,771 12/1965 Hopping 84/l.26 Re.26, 533 3/1969 Cookerly etal. 84/1.16

Primary Examiner-David X. Sliney Assistant Examiner-Stanley J. WitkowskiAttorney-Gausewitz, Carr & Rothenberg ABSTRACT: A method of creating awide variety of playerinitiated musical effects, which comprisesemploying a piezoelectric transducer in contact with the string of aguitar or similar plucked musical instrument, and thereby deriving fromthe string a control pulse upon each release of the string by the pickor fingers of the musician. The control pulse is utilized to controlvarious gating and other means to create numerous rhythm, tonal andspecial effects. The apparatus comprises a string and associatedpiezoelectric transducer, in combination with an impedance changer forcreating a very high output impedance for the transducer. Pulseseparator and amplifier means are provided to separate the control pulsefrom the tone which is generated upon plucking of the string. Variousmonostable, bistable, shaper and gate means are provided to generate thedesired tonal, rhythm and other effects.

/7 7 39 e 70 ZgZg M/PZDAA/Cf' p 68 $9 (/2 Z 4 rem/mug MA/6a, 35350104702 AND AIM/710C759 mo/vosmau 52974522 M0/V057481' Momma ag J---7s l 1 I 79 6 so m7 av?! -r/ N I as 5/14/ 5? SHAPH, 9/ a5 7 7 0/)?AM; LI 57 4M x PATENTEnnuv 9 197i SHEET 1 BF 3 ,4 TOPA/EVS' STRINGEDMUSICAL INSTRUMENT WITH PIEZOELECTRIC TRANSDUCER PROVIDING GATE CONTROLAND MUSIC SIGNALS BACKGROUND OF THE INVENTION 1. Field of the InventionThis invention relates to the field of musical instruments which areplucked by the fingers or by a hand-held pick, and which are associatedwith mechanical-electrical transducer means and amplifier-loudspeakermeans.

2. Description of the Prior Art It has become common, in associationwith electrical musical instruments such as electric guitars, to providerhythm circuits adapted to simulate various instruments, etc., so thatthe guitarist and his audience may feel that more than one instrument ispresent. Reference is made, for example to U.S. Pat. Nos. 3,146,290,3,383,452 and Re. 26,521. The apparatus for producing such rhythmefi'ects has a major defect, however, in that the guitarist cannotcontinuously vary the tempo at which the rhythm effects are beingcreated. Thus, the guitarist initially sets a knob on therhythm-creating apparatus in order to adjust the tempo, but the tempo(once determined) remains constant throughout the entire piece. This maybe equated to the guitarists getting on a merry-go-round and stayingthere. He cannot change the tempo unless he stops playing and resets theknob.

It has been proposed to provide electrically conductive picks forplucked instruments, and to employ circuit means for creating variouseffects in response to touching of such electrically conductive picks tothe strings. Reference is made, for example, to U.S. Pat. No. 3,290,425.This, however, has the serious disadvantage that the pick must beelectrically conductive and must be connected to a wire, with consequentadded circuitry, nuisance, etc. It is not satisfactory, in such devices,to pluck the strings with the fingers only.

The indicated U.S. Pat. No. 3,290,425, and also U.S. Pat. No. 3,116,357,provide various control or gate circuits responsive to the picking or toa separate electromagnetic pickup.

It is known in the field of electric organs to create control signals inresponse to pressing of the organ key, for example by means of a switchoperated by the key. Also, various percussion circuits, etc., are commonin organs as disclosed (for example) in U.S. Pat. No. 3,160,694.

To the best of the knowledge of applicant, it has not previously beenknown in the field of plucked musical instruments to employ the samemechanical-electrical transducer which senses the string vibrations forthe purpose of creating control pulses when, and only when, the pick orfinger of the guitarist releases the string. Any pick employed with thepresent guitar need not be electrically conductive, and the strings maybe plucked by the fingers instead of by a pick. No special frets, noadditional wiring of the instrument, and no additional transducers arerequired. With the present invention, a guitarist playing a guitar ofthe type employing piezoelectric transducers may have control over therhythm, tonal and other effects throughout the entire piece, and need nolonger remain at the rhythm which was determined by the setting of theknob before initiation of playing. In addition, and very importantly,the present invention permits simulation of a banjo, for example.

SUMMARY OF THE INVENTION The invention comprises a method of creatingplayer-controlled rhythm and other effects by providing a piezoelectrictransducer in association with the string of a guitar or the like,employing such transducer to generate a control pulse when the string isreleased by the pick or finger of the guitarist, and rising such controlpulse to determine the speed or tempo of rhythm-creating means, gatingmeans, etc. Alternatively, the control pulse is used to cut ofi thesound a short time period after each release, thus simulating a banjo.The method further comprises feeding the control pulse from thepiezoelectric transducer into an impedance changer having a very highinput impedance, whereby to aid in separation of the control pulse fromthe remainder of the wave generated by vibration of the string. Themethod additionally comprises providing rhythm-creating circuitry whichis initiated by operation of the control pulse and at repeatedpredetermined times, whereby the musician can change tempo at the end ofany one of such times.

The apparatus of the invention includes a guitar string in combinationwith a piezoelectric transducer, an impedance changer having a very highinput impedance and into which the transducer output is fed, a pulseseparator and amplifier to separate the control pulse from the wavegenerated in response to continued vibration of the string, and gatingand rhythm-creating means controlled by the control pulse. Thelast-named means includes a bistable circuit and a series of monostablecircuits, to provide predetermined repeated rhythm effects which areinitiated by a.control pulse at periodic intervals throughout eachmusical rendition. Shaper means are provided to determine the envelopeof the wave which passes through the gating means to the amplifier andloudspeaker means.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram,primarily in block form, illustrating one form of the method andapparatus of the invention;

FIG. 2 is a wiring diagram illustrating the impedance changer, and thepulse separator and amplifier circuit, which are shown at the upperportion of FIG. 1;

FIG. 3 is a schematic side elevational view illustrating a guitar stringand the associated piezoelectric transducer and bridge means;

FIG. 4 is an illustration of the voltage wave which is present at apoint between the impedance changer and the pulse separator andamplifier circuit; and

FIG. 5 illustrates the voltage waveform at the output of the pulseseparator and amplifier.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring first to FIG.3, a guitar body and/or neck is represented schematically at I0, havingconnected thereto at 11 and I2 the ends of a string 13 adapted to beplucked by the guitarist, either with a hand-held pick or with thefingers. A bridge 14 is provided adjacent one end 12 of the string, andis conventionally referred to as the nut. A second bridge 15 is providedadjacent the other end 11 of the string. The bridge 15 is composed of abase 16 on which is disposed a piezoelectric transducer 17. Thetransducer 17 supports the string 13 and is thus compressed in varyingdegrees depending upon the condition of the string.

Transducer 17 may be of various types but is preferably ceramic, beingformed (for example) of barium titanate or lead zirconate.

The arrangement shown in FIG. 3 is conventional, as piezoelectricpickups (mechanical-electrical transducers) have been used inassociation with guitars and the like. It is a major feature of thepresent invention that the conventional arrangement illustrated in FIG.3 is employed to create the control and rhythm efiects indicated aboveand hereinafter in this specification.

Referring next to FIG. 1, the transducer 17 is illustrated as beingconnected through an impedance changer 18 with a pulse separator andamplifier 19. These elements I8 and 19 will now be described in detailand in connection with FIG. 2.

As shown in FIG. 2, one side of transducer 17 is grounded at 21. Theother side of the transducer is connected through a lead 22 to the baseof a Darlington connection 23. which constitutes one very effective formof impedance changer 18. The Darlington connection has a very high inputimpedance and a low output impedance, being described (for example) onpage 15 of the Handbook of Basic Transistor Circuits and Measurements,"John Wiley & Sons, Inc., Semiconductor Electronics Education Committee,Volume 7. Also, reference is made to the silicon monolithic Darlingtonamplifiers manufactured by General Electric Company under its Nos.D16Pl, DI6P2, DI6P3 and DI6P4.

The Darlington connection 23, and other circuitry illustrated in FIG. 2,are biased from a positive lead 25 and a negative lead 26, the latterbeing grounded at 27. For example, positive lead 25 may be supplied fromthe positive terminal of a battery 28 the negative tenninal of which isgrounded at 29.

The collectors in Darlington connection 23 are connected through a lead31 to positive lead 25, whereas the emitter of the Darlington isconnected through an emitter load resistor 32 to negative lead 26.

The above-indicated lead 22 from transducer 17 is connected through avery high resistor 33 to the junction between two series-related andmuch smaller resistors 34 and 35. Such series-related resistors areconnected between the positive and negative leads 25 and 26.

The various resistors determine the bias of the Darlington connection23. The very high (for example, 10 megohms) resistor 33 forces thesignal present in lead 22 to pass through the Darlington instead ofbeing grounded through the lowervalue (for example, l kilohms) resistor35. Thus, the Darlington connection 23 is caused to effect ahigh-impedance loading of the piezoelectric or ceramic transducer(pickup) 17, the Darlington acting as an impedance transformer orimpedance changer. The purpose of this very high impedance which loadsthe transducer 17 is to cause a welldefined separation between what willbe termed a control pulse" and the music," as next described inconnection with FIG. 4.

Referring to FIG. 4, there is illustrated the voltage which results atthe output of Darlington connection 23 (impedance changer 18) inresponse to two successive pluckings or pickings of the string 13 (FIG.3) associated with the piezoelectric transducer 17. Two control pulses"37 are shown in FIG. 4, each of such pulses resulting from (andimmediately following) the release of the string 13 by the pick orfinger of the musician. Also shown in FIG. 4 are the ensuing music" waveportions 38 which follow the respective control pulses 37.

Of particular importance is the fact that, especially when thepiezoelectric transducer feeds into a very high-impedance load as in thepresent circuit, the control pulses 37 project major distances on oneside of the horizontal or X-axis, whereas the music portions 38 of thewave are largely disposed near the axis or on the other side thereof. Itis therefore possible, by using circuitry such as that describedhereinafter relative to the pulse separator and amplifier circuit I9, toseparate the control pulses 37 from the music portions 38, and to usesuch control pulses 37 to perform various functions as stated below.

If the load into which the transducer 17 feeds were very much lower, forexample if the resistor 33 were only I or 2 megohms instead of megohrns,the control pulses would be much less prominent and would be lessreadily separable from the remaining portions 38 of the wave. It is forthis reason that the load into which the piezoelectric transducer feeds(namely, the impedance changer 18) is made extremely high, preferablymuch higher than the high-impedance loads into which piezoelectrictransducers normally feed.

Proceeding next to a description of the pulse separator and amplifiercircuit 19, to which the output of the Darlington connection 23(impedance changer I8) is supplied via a coupling capacitor 39, thisincludes an NPN transistor 41. The emitter transistor 41 is connectedthrough an emitter resistor 42 to negative lead 26, and the collector isconnected through a collector load resistor 43 to positive lead 25. Thebase of transistor 41 connects to capacitor 39, and is also connectedthrough resistors 44 and 45 to positive and negative leads 25 and 26,respectively. A gain-determining network, comprising a series-relatedresistor 46 and capacitor 47, is connected in parallel with resistor 42between the emitter of transistor 41 and ground lead 26. Such networkincreases the gain to the transistor 41 without adversely affecting thebias thereof. The bias of the amplifier formed by transistor 41 andassociated elements should be such as to prevent clipping of the controlpulses 37 (FIG. 4).

The output of the amplifier, namely, the collector of transistor 41,connects to a coupling capacitor 48 and thus to a discriminating orclipping circuit adapted to transmit the control pulses 37 effectivelywhile substantially blocking or eliminating the music portions 38 of thewave. Such circuit includes diodes 50 and 51 and an NPN transistor 52,the latter preferably being biased in such manner that it willdiscriminate against any remaining portions of the music wave 38.

Stated more specifically, the capacitor 48 is connected through a lead53 to diode 51, and such diode in turn is connected through aseries-related resistor 54 and capacitor 55 to the base of transistor52. The diode 50 is connected in parallel with a resistor 56 betweenlead 53 and lead 26. An additional resistor, numbered 57, is connectedbetween lead 26 and the junction between diode 51 and resistor 54.

Diode 50 is oriented in such manner that it will tend to pass to groundthe music portions 38 of the wave (FIG. 4). The resistors 56 and 57 aresufficiently high, for example kilohms, that the control pulses 37 willnot be attenuated (passed to ground) in any major degree. Diode SI is sooriented that it tends to block the music portions 38 (FIG. 4) whilepassing effectively the control pulses 37.

The orientation of diodes 50 and 51 is correlated to the type andorientation of the piezoelectric transducer 17 with which the circuit isassociated. In the illustrated circuit, it is assumed that transducer 17is such that the control pulse portions 37 of the wave passed throughcoupling capacitor 39 are positive, as shown in FIG. 4. Such positivecontrol pulses 37 are inverted by transistor 41 and are thereforenegative at lead 53. The negative control pulses do not tend to passthrough the diode 50 since the anode of such diode is remote fromnegative lead 26. correspondingly, such negative pulses are not blockedby diode 51 since lead 53 is connected to the cathode of such diode. Ifthe polarity of the pickup 17 were reversed, each of diodes S0 and 51would also be reversed.

The transistor 52 forms part of a second amplifier which is connectedgenerally as is the first-described amplifier. Thus, the collector oftransistor 52 is connected through a collector resistor 58 to positivelead 25, and the emitter of such amplifier is connected through aresistor 59 to negative lead 26. Series-related resistor 60 andcapacitor 6! connect the emitter of transistor 52 to ground lead 26.Resistors 62 and 63 extend, respectively, from the base of transistor 52to positive lead 25 and to ground. The series-related resistor andcapacitor 60 and 61 serve, as do elements 46 and 47, to change the gainof the associated amplifier without affecting the bias.

The output at pulse separator and amplifier circuit I9 is an amplifiedcontrol pulse 37, as shown in FIG. 5. Such pulse is substantially freeof the music wave portions, but it is to be understood that some smallparts of the music wave portions may be tolerated if they are not ableto start or affect the operation of the monostable circuit 70 mentionedhereinafter.

In addition to (or in place of) circuit 19, the peak portions of controlpulses 37 may be separated from music 38 by a peak follower circuit. Onesuch circuit is shown by FIG. 654 on page of the Handbook of BasicTransistor Circuits and Measurements," cited above.

Referring again to FIG. 1, the amplified control pulse 37 (FIG. 5) isdelivered through a coupling capacitor 68 and resistor 69 to amonostable (one-shot) multivibrator 70. Such monostable generates aclean, uniform-value output pulse, of uniform duration, upon eachactuation by a pulse 37 from pulse separator circuit 19.

The output of the monostable multivibrator 70 is connnected trough alead 71 to the input or trigger terminal of a bistable multivibrator(flip-flop) 73. One output of the bistable multivibrator 73 is connectedthrough a lead 74 to any desired number of series-related monostable(one-shot) multivibrators 75, 76, 77, etc. One output of the end one ofthe monostables, number 77 in the illustrated form of the invention, isconnected through a clear line 78 to the clear terminal of the bistable73.

The remaining output terminals of the respective circuits 73, 75, 76 and77 are connected through switches 79-82, respectively, to a lead 84which is connected to the inputs of two (or more) shaper circuits 85 and87. The outputs of such circuits 85 and 87 are connected throughswitches 89 and 88, respectively, to control terminals of a dual gatecircuit 90.

The music generated by the piezoelectric transducer 17 is transmitteddirectly through a lead 91 (FIGS. 1 and 2) to the input of dual gate 90.The output of such gate is connected through a power amplifier 93 to'aloudspeaker 94.

The monostable multivibrators 70, 75, 76 and 77 may be of conventionalconstruction, and each incorporates means to determine the time delaywhich elapses between reception of an input or trigger pulse andtransmission of an output pulse. However, in the case of monostable 70no such time delay need be provided, because such monostable is normallyset to deliver an output pulse immediately upon reception of the inputor trigger pulse 37.

Bistable multivibrator 73 may also be of conventional construction, anddelivers output pulses to lead 74 and to switch 79 immediately uponreception of an input pulse from the monostable 70 through lead 71. Thetwo shapers 8S and 87 are also of conventional construction, and deliverenvelopecontrol waves which are determined by the characteristics of theparticular circuit. For example, shaper circuit 85 may deliver awaveform such as that indicated at 96, and which is characterized by arelatively steep rise followed by a slowdeclining ramp. Conversely,shaper circuit 87 may deliver one or more relatively steep and shortpulses as indicated at 97.

The dual gate 90 is so constructed that the music passed therethroughfrom lead 91 to amplifier 93 is envelope controlled in accordance withone or both of the waveforms 96, 97, etc., as. desired. This, forexample, when switch 89 is closed the volume of the sound transmittedthrough gate 90 will be loud at the initial portion of wave 96 andprogressively softer toward the end portions thereof. If there is noenvelope signal at either gating terminal, no signal may pass throughthe gate from lead 91 to amplifier 93. One form of dual gate 90 whichmay be employed is a MOS Dual Keyer Gate with Snub Inputs, manufacturedby Motorola Semiconductor Products, lnc., under MCl l2OP.

DESCRIPTION OF THE METHOD Stated generally, the present method comprisesassociating a piezoelectric transducer, such as is indicated at 17, withthe string 13 (FIG. 3) of a hand-plucked musical instrument such as aguitar. The string 13 is then plucked by the fingers or by a handheldpick, and the resulting signal (FIG. 4) is fed through a veryhigh-impedance circuit to a pulse separator and amplifier. The methodthen comprises separating each control pulse 37 (FIG. 4) from theremainder 38 of the wave, in order to derive the isolated control pulsesillustrated in FIG. 5. Thereafter, each control pulse (or a counterpartthereof) is transmitted to gating means, and the music signal from thetransducer 17 is also transmitted to such gating means (for example, thedual gate 90), whereby the music signal may not be transmitted unless(and to the extent that) the control pulse so permits. The resultingcontrolled signal from the transducer is amplified and delivered to aloudspeaker such as is represented at 94.

In the described manner, therefore, the guitarist or other musician hascomplete control over the tempo of the music, because such tempo is notsolely determined by some preset electronic circuit but instead respondsto the frequency of repetition of the control pulses 37, such frequencybeing under the direct control of the guitarist.

Stated more definitely, and with particular reference to the circuitillustrated in FIG. 1, the method of the invention comprises passing theindicated control pulses to the input of the bistable multivibrator 73.Assuming that switch 79 is closed, bistable 73 immediately transmits anoutput to lead 84. If switch 89 is closed and switch 88 is open, thesignal from lead 84 is transmitted only through shaper 85 and to onecontrol input of dual gate 90. Then, the signal which passes throughlead 91 from transducer 17 to gate 90 is caused to have an envelope asindicated at 96. Such signal is amplified by amplifier 93 and convertedby loudspeaker 94 to sound waves.

Triggering of bistable 73 also causes an output pulse to be deliveredthrough lead 74 to monostable 75. Such monostable has a built-in timedelay the duration of which may be predetermined by the musician. At theend of such time delay, and not before, output pulses are delivered bothto monostable 76 and through switch (if in closed condition) to lead 84.Correspondingly, monostables 76 and 77 each have builtin time delayswhich may be independently and individually preadjusted by the musician.Thus, after each such monostable 76 and 77 is triggered, and at the endof a time period predetermined by the guitarist, output signals aretransmitted through the respective switches 81-82 (if closed) to lead84.

The characteristics of the bistable multivibrator 73 are such that itwill not transmit any additional output pulses until a clear signal istransmitted thereto through clear line 78 from the output of monostable77. Therefore, once the bistable 73 has been initially triggered, it maynot be triggered again until cleared by a pulse transmitted throughclear line 78. It follows that all of the control pulses 37 whichemanate from pulse separator 19 and monostable 70 will be of no effectuntil the bistable 73 is set by a pulse from the clear line. Then one,and only one, pulse 37 from the pulse separator and amplifier 19 willreinitiate the entire sequence of operation.

Let it be assumed, for example, that all of switches 79-82 are closed,that switch 88 is closed and switch 89 is open. The first control pulsedelivered to bistable 73 causes operation of dual gate 90 to immediatelytransmit music having an envelope as shown at 97. Thereafter, and assoon as the monostable 75 delivers an output pulse, the dual gate 90will again transmit a burst of music having the envelope 97. Third andfourth bursts of music then result in sequence, and with various timedelays, when the monostables 76 and 77 deliver their outputs to theshaper 87 and thence to the dual gate 90. Closing of switch 89 effectssimultaneous transmission of pulses from line 84 through bothshapers 85and 87 to the dual gate, thereby creating superimposed envelope effects.

As but one of a very wide variety of modes of operation which may beeffected, switch 79 may be closed, switches 80-82 may be opened and allof the monostables 75, 76 and 77 may be set for exceedingly short timedelays. Then, switch 88 is closed and switch 89 is opened so that theenvelope 97 transmitted to dual gate 90 will be very short. With such asetting, each note struck by the guitarist will be operative to causebistable 73 to transmit a pulse through shaper 87 to dual gate 90, butthis pulse will be short and may, for example, simulate a banjo. Becauseof the exceedingly short time delays set in monostables 75-77, a clearpulse will be transmitted through line 78 to the bistable substantiallyimmediately after transmission of an output pulse through switch 79 andshaper 87 to the gate 90.

Various other circuits, for example those simulating drum sounds,marimba sounds, etc., may be controlled by the control pulses in themanner described above relative to circuits 73 and 75-77. For example,let it be assumed that a drumsound generating circuit is substituted forswitch 79, another such drum-sound circuit is substituted for switch 80,another is substituted for switch 81, and another is substituted forswitch 82. Let it also be assumed that lead 84 is connected by circuitmeans, not shown, directly to amplifier 93 and thus to speaker 94.Accordingly, each time the circuits 73 and 75-77 produce outputs, drumsounds will be heard by a listener to the loudspeaker, and at timeperiods determined by die delays set in the monostables 75-77.

It is to be understood that, in a six-stringed instrument such as aguitar, six different ones of the circuits illustrated in FIG. 1 may beprovided (one circuit for each string). However, all of the strings mayfeed into common amplifier 93 and loudspeaker 94. It is within the scopeof the invention to cause different strings of the instrument to operatedifferent instruments" (different sound-effect circuits).

It is to be noted that the music sound transmitted through lead 91 todual gate-90 is normally continuous since the musician usually permitsthe string 13 to continue vibrating (dwell) after picking. I

it is within the scope of the invention to provide electromagneticpickup means responsive to vibration of the various strings, in order togenerate the wave of music voltage, and to use in association with suchelectromagnetic pickup means one or more piezoelectric transducers togenerate control voltage pulses 37 as described heretofore in thisspecification.

The foregoing detailed description is to be clearly understood as givenby way of illustration and example only, the spirit and scope of thisinvention being limited solely by the appended claims.

lclaim:

l. A method of creating desired special musical effects with a stringedmusical instrument of the type wherein the strings are plucked by thefingers or by a hand-held pick, which comprises:

employing a piezoelectric transducer to sense the vibrations of at leastone string of said instrument,

whereby said transducer generates a control pulse of voltage in responseto, and immediately upon, the release of said one string by a hand-heldpick or by the fingers of the musician, and

whereby said transducer also generates a music wave of voltage after,and in response to, said release of said one string, and

employing said control pulse of voltage to create desired specialmusical effects.

2. The method as recited in claim 1, in which said method furthercomprises passing to amplifier and loudspeaker means at least part ofthe said music wave of voltage which is generated by said transducerafter, and in response to, said release of said one string.

3. The invention as claimed in claim 1, in which said method furthercomprises separating said control pulse of voltage from the said musicwave of voltage which is generated by said transducer after, and inresponse to, said release of said one string, and passing said controlpulse of voltage to electronic circuit means adapted to create desiredspecial musical effects.

4. The invention as claimed in claim 3, in which said method furthercomprises effecting said separation by passing said control pulse ofvoltage and said associated music wave of voltage into a veryhigh-impedance load, whereby to cause said control pulse of voltage tobe generally on one side of a horizontal axis, and whereby to cause saidmusic wave of voltage to be offset primarily on the opposite side ofsaid horizontal axis, and thereafter passing said control pulse ofvoltage and said music wave of voltage through pulse-separator circuitryadapted to produce an output comprising said control pulse of voltageand substantially free of said music wave of voltage.

5. The invention as claimed in claim 4, in which said method furthercomprises passing a voltage wave from said transducer to amplifier andloudspeaker means independently of said pulse-separator circuitry.

6. The invention as claimed in claim 1, in which said method furthercomprises passing a voltage wave from said transducer through gate meansto amplifier and loudspeaker means, and employing sad control pulse ofvoltage to operate said gate means in a manner creating desired musicaleffects.

7. The invention as claimed in claim 1, in which said method furthercomprises employing said control pulse of voltage to create rhythmeffects.

8. The invention as claimed in claim 1, in which said method furthercomprises passing a voltage wave from said transducer through gate meansto amplifier and loudspeaker means, and employing said control pulse ofvoltage to effect operation of said gate means to block transmission ofsaid voltage wave through said gate means a short time period aftergeneration of said control pulse of voltage.

9. A method of creating rhythm effects with a stringed musicalinstrument of the type wherein the strings are plucked by a hand-heldpick or by the fingers of the musician, which comprises:

providing a substantial number of multivibrator circuits in seriesrelationship, at least the first of said multivibrator circuits beingbistable,

deriving a clear signal from the last of said multivibrator circuits andsupplying such signal to the clear input of said first and bistablemultivibrator circuit,

deriving a control pulse of voltage from at least one string of saidmusical instrument in response to release of such string by the pick orfinger of the musician,

feeding each such control pulse to said first multivibrator circuit,

whereby said first multivibrator circuit is caused to change state whenone of said control pulses is received thereby, but only if such firstmultivibrator circuit is in cleared condition, and

generating sequential rhythm efiects in response to operation of saidseries-related multivibrator circuits,

whereby the musician can, by changing the frequency of repetition ofreleases of said string, control the repetition rate of the varioussequences of generated rhythm effects.

10. The invention as claimed in claim 9, in which said method furthercomprises employing, as all of said multivibrators other than said firstmultivibrator circuit, monostable multivibrators the time delays ofwhich may be predetennined by the musician.

11. The invention as claimed in claim 9, in which said method furthercomprises generating said rhythm effects by using the outputs of saidmultivibrators to control the operation of gate means, deriving fromsaid instrument a musical signal corresponding to the vibration of astring of said instrument, and feeding said musical signal through saidgate means to amplifier and loudspeaker means.

12. The invention as claimed in claim 11, in which said method furthercomprises employing shaper circuitry to control said gate means inresponse to actuation of said shaper circuitry by the outputs of saidmultivibrators, whereby the envelopes of the portions of said musicalsignal passed through said gate means correspond to the output of saidshaper circuitry.

13. The invention as claimed in claim 9, in which said step of derivingsaid control pulse is effected by providing a piezoelectric transducerin association with said one string, and substantially separating saidcontrol pulse from the voltage wave generated by said transducer inresponse to plucking and consequent vibration of said string.

14. The invention as claimed in claim 9, in which said method furthercomprises deriving said control pulse of voltage immediately uponrelease of such string by the pick or finger of the musician.

l5. Circuitry for creating special musical effects in association with aguitar having piezoelectric transducer means to sense the vibrations ofat least one string thereof, which comprises:

separator means adapted to be connected to said transducer means toreceive the voltage wave therefrom and to separate from said voltagewave the control pulse of voltage which results from, and immediatelyupon, the release of at least one string of the guitar by the pick orfinger of the guitarist,

means to generate special musical efi'ects, and

means to supply said control pulse to said special-effect generatingmeans, whereby the operation of said special-efiect generating means isdetermined by the plucking of said one guitar string by the guitarist.

16. The invention as claimed in claim 14, in which amplifier andloudspeaker means are provided, and in which connector means areprovided to connect said piezoelectric transducer means on the guitar tosaid amplifier and loudspeaker means.

17. The invention as claimed in claim 16, in which said connector meansincludes gate means, and in which means are provided to control saidgate means in response to said control pulses.

18. The invention as claimed in claim 15, in which said circuitry iscombined with a guitar wherein said piezoelectric transducer means isprovided in engagement with at least said one string of the guitar.

19. Apparatus for generating special musical effects, which comprises:

a tensioned string adapted to be plucked by a hand-held pick or by thefinger of a musician, a piezoelectric transducer provided invibration-sensing relationship relative to said string whereby togenerate a voltage wave corresponding to the vibrations of said string,said voltage wave including a control pulse portion responsive to andimmediately following release of said string by a hand-held pick or bythe finger of the musician,

said voltage wave also comprising a music portion following said controlpulse portion and responsive to continued vibrations of said string,

means to substantially separate said control pulse portion from saidmusic portion,

special-effect generating circuitry,

means to supply said separated control pulse portion to saidspecial-effect generating circuitry, and

means to supply at least part of the voltage wave from saidpiezoelectric transducer to amplifier and loudspeaker means.

20. The invention as claimed in claim 19, in which said 'rneans toseparate said control pulse portion from said music portion includes animpedance changer which presents a very high impedance to saidpiezoelectric transducer.

21. The invention as claimed in claim 20, in which said means toseparate said control pulse from said music portion further comprisesdiscriminator and clipper circuitry adapted to discriminate against saidmusic portion and to transmit said control pulse portion.

22. The invention as claimed in claim 19, in which said special-effectgenerating circuitry includes gate means, means to control said gatemeans in response to said control pulse portion, means to supply to theinput of said gate means the voltage wave from said piezoelectrictransducer, and amplifier and loudspeaker means connected to the outputof said gate means.

23. The invention as claimed in claim 19, in which said special-effectgenerating circuitry includes a substantial number of series-relatedmultivibrator circuits, at least the first one of said multivibratorcircuits being bistable, a clear line connecting an output of the lastof said multivibrator circuits to the clear input of said bistablemultivibrator circuit, in which means are provided to supply saidcontrol pulse portion to an input of said first and bistablemultivibrator circuit, and in which said special-effect generatingcircuitry further includes means connected to the respective outputs ofsaid multivibrator circuits to create special efiects whensaid variousmultivibrator circuits supply output pulses.

24. The invention as claimed in claim 23, in which at least some of saidmultivibrator circuits include time delay means variable by the musicianin order to predetermine the time se uence of special effects.

5. The invention as claimed in claim 24, in which all of saidmultivibrator circuits excepting said first and bistable multivibratorcircuit are monostable multivibrators.

26. The invention as claimed in claim 23, in which gate means areprovided, in which means are provided to supply the voltage wave fromsaid piezoelectric transducer to the input of said gate means, in whichthe output of said gate means is connected to amplifier and loudspeakermeans, and in which shaper means are provided, the output of said shapermeans being connected to a control terminal of said gate means, theinput of said shaper means being connected to the outputs of saidmultivibrator circuits.

27. The invention as claimed in claim 26, in which switch means areprovided to determine which multivibrator circuits are connected to saidshaper means.

28. The invention as claimed in claim 26, in which first and secondshaper means are provided, each of said first and second shaper meansgenerating a wave of different shape, in which said gate means is a dualgate, in which the outputs of said shaper means are respectivelyconnected to the two control terminals of said dual gate, and in whichthe inputs of said shaper means are connected to said variousmultivibrators.

29. The invention as claimed in claim 28, in which switch means areprovided to detennine which of said shaper means is connected in thecircuit.

30. Electrical musical instrument apparatus, which comprises:

a guitar having a string,

a piezoelectric transducer to support a portion of said string andthereby sense the vibrations thereof,

said transducer generating a control pulse of voltage in response to,and immediately upon, release of said string by a hand-held pick or bythe fingers of the musician,

special-effect generating means, and

means to initiate operation of said special-effect generating means inresponse to said control pulse.

31. A method of creating special musical effects with a stringed musicalinstrument of the type wherein the strings are plucked by the fingers orby a hand-held pick, which comprises:

transducing the vibrations of at least one string of said instrument tothereby generate an electrical signal corresponding to the vibrations ofsuch one string,

said vibrations and said corresponding signal occurring immediately uponrelease of the string and also after such release,

converting that part of said corresponding signal occuring immediatelyupon release of the string into a control pulse, and

employing said control pulse to initiate operation of an elec tronicmeans for generating a special musical sound effect.

8 i i l UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.468 Dated N v r 197] Inventor(s) Chauncey R. Evans It is certified thaterror appears in the above-identified patent andthat said Letters Patentare hereby corrected as shown below:

Column 9, line 6 (line 1 of claim 16) cancel "14" and substitute 15Signed and sealed this 26th day of December 1972.

(SEAL) EDWARD M.F1JETCHER,JR. ROBERT GOJJJJSCHALK Attesting OfficerCommissioner of Patents

1. A method of creating desired special musical effects with a stringedmusical instrument of tHe type wherein the strings are plucked by thefingers or by a hand-held pick, which comprises: employing apiezoelectric transducer to sense the vibrations of at least one stringof said instrument, whereby said transducer generates a control pulse ofvoltage in response to, and immediately upon, the release of said onestring by a hand-held pick or by the fingers of the musician, andwhereby said transducer also generates a music wave of voltage after,and in response to, said release of said one string, and employing saidcontrol pulse of voltage to create desired special musical effects. 2.The method as recited in claim 1, in which said method further comprisespassing to amplifier and loudspeaker means at least part of the saidmusic wave of voltage which is generated by said transducer after, andin response to, said release of said one string.
 3. The invention asclaimed in claim 1, in which said method further comprises separatingsaid control pulse of voltage from the said music wave of voltage whichis generated by said transducer after, and in response to, said releaseof said one string, and passing said control pulse of voltage toelectronic circuit means adapted to create desired special musicaleffects.
 4. The invention as claimed in claim 3, in which said methodfurther comprises effecting said separation by passing said controlpulse of voltage and said associated music wave of voltage into a veryhigh-impedance load, whereby to cause said control pulse of voltage tobe generally on one side of a horizontal axis, and whereby to cause saidmusic wave of voltage to be offset primarily on the opposite side ofsaid horizontal axis, and thereafter passing said control pulse ofvoltage and said music wave of voltage through pulse-separator circuitryadapted to produce an output comprising said control pulse of voltageand substantially free of said music wave of voltage.
 5. The inventionas claimed in claim 4, in which said method further comprises passing avoltage wave from said transducer to amplifier and loudspeaker meansindependently of said pulse-separator circuitry.
 6. The invention asclaimed in claim 1, in which said method further comprises passing avoltage wave from said transducer through gate means to amplifier andloudspeaker means, and employing said control pulse of voltage tooperate said gate means in a manner creating desired musical effects. 7.The invention as claimed in claim 1, in which said method furthercomprises employing said control pulse of voltage to create rhythmeffects.
 8. The invention as claimed in claim 1, in which said methodfurther comprises passing a voltage wave from said transducer throughgate means to amplifier and loudspeaker means, and employing saidcontrol pulse of voltage to effect operation of said gate means to blocktransmission of said voltage wave through said gate means a short timeperiod after generation of said control pulse of voltage.
 9. A method ofcreating rhythm effects with a stringed musical instrument of the typewherein the strings are plucked by a hand-held pick or by the fingers ofthe musician, which comprises: providing a substantial number ofmultivibrator circuits in series relationship, at least the first ofsaid multivibrator circuits being bistable, deriving a clear signal fromthe last of said multivibrator circuits and supplying such signal to theclear input of said first and bistable multivibrator circuit, deriving acontrol pulse of voltage from at least one string of said musicalinstrument in response to release of such string by the pick or fingerof the musician, feeding each such control pulse to said firstmultivibrator circuit, whereby said first multivibrator circuit iscaused to change state when one of said control pulses is receivedthereby, but only if such first multivibrator circuit is in clearedcondition, and generating sequential rhythm effects in response tooperation of said series-reLated multivibrator circuits, whereby themusician can, by changing the frequency of repetition of releases ofsaid string, control the repetition rate of the various sequences ofgenerated rhythm effects.
 10. The invention as claimed in claim 9, inwhich said method further comprises employing, as all of saidmultivibrators other than said first multivibrator circuit, monostablemultivibrators the time delays of which may be predetermined by themusician.
 11. The invention as claimed in claim 9, in which said methodfurther comprises generating said rhythm effects by using the outputs ofsaid multivibrators to control the operation of gate means, derivingfrom said instrument a musical signal corresponding to the vibration ofa string of said instrument, and feeding said musical signal throughsaid gate means to amplifier and loudspeaker means.
 12. The invention asclaimed in claim 11, in which said method further comprises employingshaper circuitry to control said gate means in response to actuation ofsaid shaper circuitry by the outputs of said multivibrators, whereby theenvelopes of the portions of said musical signal passed through saidgate means correspond to the output of said shaper circuitry.
 13. Theinvention as claimed in claim 9, in which said step of deriving saidcontrol pulse is effected by providing a piezoelectric transducer inassociation with said one string, and substantially separating saidcontrol pulse from the voltage wave generated by said transducer inresponse to plucking and consequent vibration of said string.
 14. Theinvention as claimed in claim 9, in which said method further comprisesderiving said control pulse of voltage immediately upon release of suchstring by the pick or finger of the musician.
 15. Circuitry for creatingspecial musical effects in association with a guitar havingpiezoelectric transducer means to sense the vibrations of at least onestring thereof, which comprises: separator means adapted to be connectedto said transducer means to receive the voltage wave therefrom and toseparate from said voltage wave the control pulse of voltage whichresults from, and immediately upon, the release of at least one stringof the guitar by the pick or finger of the guitarist, means to generatespecial musical effects, and means to supply said control pulse to saidspecial-effect generating means, whereby the operation of saidspecial-effect generating means is determined by the plucking of saidone guitar string by the guitarist.
 16. The invention as claimed inclaim 14, in which amplifier and loudspeaker means are provided, and inwhich connector means are provided to connect said piezoelectrictransducer means on the guitar to said amplifier and loudspeaker means.17. The invention as claimed in claim 16, in which said connector meansincludes gate means, and in which means are provided to control saidgate means in response to said control pulses.
 18. The invention asclaimed in claim 15, in which said circuitry is combined with a guitarwherein said piezoelectric transducer means is provided in engagementwith at least said one string of the guitar.
 19. Apparatus forgenerating special musical effects, which comprises: a tensioned stringadapted to be plucked by a hand-held pick or by the finger of amusician, a piezoelectric transducer provided in vibration-sensingrelationship relative to said string whereby to generate a voltage wavecorresponding to the vibrations of said string, said voltage waveincluding a control pulse portion responsive to and immediatelyfollowing release of said string by a hand-held pick or by the finger ofthe musician, said voltage wave also comprising a music portionfollowing said control pulse portion and responsive to continuedvibrations of said string, means to substantially separate said controlpulse portion from said music portion, special-effect generatingcircuitry, means to supply sAid separated control pulse portion to saidspecial-effect generating circuitry, and means to supply at least partof the voltage wave from said piezoelectric transducer to amplifier andloudspeaker means.
 20. The invention as claimed in claim 19, in whichsaid means to separate said control pulse portion from said musicportion includes an impedance changer which presents a very highimpedance to said piezoelectric transducer.
 21. The invention as claimedin claim 20, in which said means to separate said control pulse fromsaid music portion further comprises discriminator and clipper circuitryadapted to discriminate against said music portion and to transmit saidcontrol pulse portion.
 22. The invention as claimed in claim 19, inwhich said special-effect generating circuitry includes gate means,means to control said gate means in response to said control pulseportion, means to supply to the input of said gate means the voltagewave from said piezoelectric transducer, and amplifier and loudspeakermeans connected to the output of said gate means.
 23. The invention asclaimed in claim 19, in which said special-effect generating circuitryincludes a substantial number of series-related multivibrator circuits,at least the first one of said multivibrator circuits being bistable, aclear line connecting an output of the last of said multivibratorcircuits to the clear input of said bistable multivibrator circuit, inwhich means are provided to supply said control pulse portion to aninput of said first and bistable multivibrator circuit, and in whichsaid special-effect generating circuitry further includes meansconnected to the respective outputs of said multivibrator circuits tocreate special effects when said various multivibrator circuits supplyoutput pulses.
 24. The invention as claimed in claim 23, in which atleast some of said multivibrator circuits include time delay meansvariable by the musician in order to predetermine the time sequence ofspecial effects.
 25. The invention as claimed in claim 24, in which allof said multivibrator circuits excepting said first and bistablemultivibrator circuit are monostable multivibrators.
 26. The inventionas claimed in claim 23, in which gate means are provided, in which meansare provided to supply the voltage wave from said piezoelectrictransducer to the input of said gate means, in which the output of saidgate means is connected to amplifier and loudspeaker means, and in whichshaper means are provided, the output of said shaper means beingconnected to a control terminal of said gate means, the input of saidshaper means being connected to the outputs of said multivibratorcircuits.
 27. The invention as claimed in claim 26, in which switchmeans are provided to determine which multivibrator circuits areconnected to said shaper means.
 28. The invention as claimed in claim26, in which first and second shaper means are provided, each of saidfirst and second shaper means generating a wave of different shape, inwhich said gate means is a dual gate, in which the outputs of saidshaper means are respectively connected to the two control terminals ofsaid dual gate, and in which the inputs of said shaper means areconnected to said various multivibrators.
 29. The invention as claimedin claim 28, in which switch means are provided to determine which ofsaid shaper means is connected in the circuit.
 30. Electrical musicalinstrument apparatus, which comprises: a guitar having a string, apiezoelectric transducer to support a portion of said string and therebysense the vibrations thereof, said transducer generating a control pulseof voltage in response to, and immediately upon, release of said stringby a hand-held pick or by the fingers of the musician, special-effectgenerating means, and means to initiate operation of said special-effectgenerating means in response to said control pulse.
 31. A method ofcreating special musical effects with a Stringed musical instrument ofthe type wherein the strings are plucked by the fingers or by ahand-held pick, which comprises: transducing the vibrations of at leastone string of said instrument to thereby generate an electrical signalcorresponding to the vibrations of such one string, said vibrations andsaid corresponding signal occurring immediately upon release of thestring and also after such release, converting that part of saidcorresponding signal occuring immediately upon release of the stringinto a control pulse, and employing said control pulse to initiateoperation of an electronic means for generating a special musical soundeffect.